Add a release note for this change.

Author: bd1976bris

llvm/docs/ReleaseNotes.md

@@ -80,6 +80,8 @@ Changes to LLVM infrastructure
 * Added the support for ``fmaximum`` and ``fminimum`` in ``atomicrmw`` instruction. The
   comparison is expected to match the behavior of ``llvm.maximum.*`` and
   ``llvm.minimum.*`` respectively.
+* On Windows, fatal usage errors no longer produce crash-style diagnostics
+  such as stack traces or bug report prompts.
 
 Changes to building LLVM
 ------------------------